Granular proteolytic enzyme composition

ABSTRACT

The invention is directed to an improvement in the storage stability of granular proteolytic enzyme compositions. The proteolytic enzymes are contained in granules to which an acidic substance has been added. The granules will comprise a neutral or alkaline carrier material, for example an alkali metal phosphate; a gluing agent, for example a nonionic surface active agent; a proteolytic enzyme and an acidic material, for example citric acid.

AU 165 x United States Patent 11 1 van Kampen et al.

1 51 Mar. 27, 1973 GRANULAR PROTEOLYTIC ENZYME COMPOSITION Inventors:Daniel Marten van Kampen, Vlaardingen; Foscarina Pasztor nee Rozzo,Abcoude, both of Netherlands Assignee: Lever Brothers Company, New

Y0rk,N.Y.

Filed: June 5, 1972 Appl. No.: 259,638

Related U.S. Application Data Continuation-impart of Ser. No. 20,019,March 16, 1970, abandoned.

US. Cl. ..252/110, 195/63, 195/68, 252/89, 252/91, 252/97, 252/100,252/132, 252/134, 252/136, 252/142, 252/174,

Int.Cl ..Clld 7/08,Cl1d 7/42,C11d 17/06 Field of Search ....195/63, 68;252/89, 132,135, 252/D1G. 12

References Cited UNITED STATES PATENTS 12 1971 Davisetal ..252 531Primary Examiner-Leon D. Rosdol Assistant Examiner-Dennis l... AlbrechtAttorney-Louis F. Kline, Jr. et al.

[57] ABSTRACT The invention is directed to an improvement in the storagestability of granular proteolytic enzyme compositions. The proteolyticenzymes are contained in granules to which an acidic substance has beenadded. The granules will comprise a neutral or alkaline carriermaterial, for example an alkali metal phosphate; a gluing agent, forexample a nonionic surface active agent; a proteolytic enzyme and anacidic material, for example citric acid.

5 Claims, No Drawings GRANULAR PROTEOLYTIC ENZYME COMPOSITIONCross-Reference to Related Application This application is acontinuation-in-part of our earlier filed application Ser. No. 20, 019,filed 16th Man, 1970 now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates to granular proteolytic enzyme compositions, adaptedto be formulated with a detergent composition, and to detergentcompositions containing these granular proteolytic enzyme compositions.

2. Description of the Prior Art Enzymic cleaning compositions are old.See, for example, German patent specifications 283,923 (Rohm, 1915) and329,958 (Rohm, 1920). The enzymes aid in cleaning by attacking the soiland stains of the soiled objects to be cleaned. Proteinaceous soil andstains are attacked by proteolytic enzymes. Such proteolytic enzymes,suitable for cleaning purposes, are normally found in the form of finepowders. Such fine powders are difficult to handle and difficult toformulate. When such fine powders are incorporated in detergentcompositions, their stability is often greatly impaired by severalingredients of the detergent composition, and by moisture, which may betaken up by the detergent composition during storage. It is believedthat this moisture brings the proteolytic enzymes into contact with theother ingredients of the detergent composition, which are harmful to theproteolytic enzymes.

It has already been proposed in US. Pat. No. 3,519,570 to enhance thestability of proteolytic enzymes by bringing them in granular form. Thisis done by rendering the surfaces of base carried detergent granulesglutinous with a low-melting, ordinarily solid, water-soluble nonionicsurface-active agent which liquet'ies between lF and 200F, andsubsequently conglutinating with said glutinous surfaces the proteolyticenzymes in a powdered form. The granules thus obtained may beadditionally coated with the nonionic surface-active agent toencapsulate the proteolytic enzymes and to protect them from moistureand other harmful ingredients.

Although such granular proteolytic enzyme compositions are much morestable than the fine, powdered proteolytic enzymes, their stability indetergent compositions is still often not satisfactory for detergentformulation purposes.

Object of the Invention It is therefore an object of the presentinvention to further improve the storage stability of granularproteolytic enzyme granules. Further objects will become apparent fromthe detailed description of the invention given hereafter.

SUMMARY OF THE INVENTION It has been found that incorporating an acidicsubstance in the nonionic layer of the granular proteolytic enzymecompositions of the type as heretofore described, greatly enhances thestorage stability of said granular proteolytic enzyme compositions. Thepresent invention therefore relates to a granular proteolytic enzymecomposition, adapted to be formulated with a detergent composition, thegranular proteolytic enzyme composition consisting essentially of:

l a core of a non-acidic carrier material 2. a coating layer enrobingsaid core, the coating layer being a nonionic surface-active agent 3.proteolytic enzymes, attached to said coating layer 4. an acidicsubstance, dissolved or dispersed in said coating layer.

In another aspect of the invention, the granular proteolytic enzymecomposition also contains an outer layer of a nonionic surface-activeagent, in which an acidic substance is dissolved or dispersed.

DETAILED DESCRIPTION OF INVENTION The granular proteolytic enzymecomposition consists essentially of l. a core of non-acidic carriermaterial 2. a coating layer of a nonionic surface-active agent enrobingsaid core, said coating layer containing an acidic substance dissolvedor dispersed therein 3. proteolytic enzymes. Core of non-acidic carriermaterial The core of the granules consists of a non-acidic carriermaterial, i.e. a neutral or alkaline carrier material, from whichgranules can be made. The particle size of the carrier material shouldlie between 0.05 mm and 1.5 mm, preferably between 0.3 and 1.5 mm. Thecarrier material should have a porosity of lying between 0.15 ml/g and lml/g preferably between 0.15 and 0.50 ml/g, determined by the mercurymethod. This method consists of adding mercury t0 the carrier materialunder vacuum and measuring the apparent mercury density in an apparatusas described by J.M. Vleeskens in his Thesis of Delft University,Holland 1959, using the equation (AHg/eHg) volume of pores (M/es), whereAHg difference in weight of mercury before and after addition to thesample eHg density of mercury M weight of sample of carrier material asdensity of sample of carrier material The carrier material must besufficiently strong, i.e. must be non-friable, and may not behygroscopic. Crystal water may be present, provided the carrier materialdoes not melt in its own water of crystallization at temperatures below40-C (as e.g. Na,SO,-l0 aq). Suitable examples of neutral and alkalinecarrier materials are alkali metal phosphates, such as penta sodium andpenta potassium triphosphate, tetrasodium pyrophosphate, sodium orpotassium orthophosphate, sodium or potassium sulphate or mixturesthereof, alkalimetal borates and carbonates, alkalimetal silicates,gelatinized starch and starch derivatives. In general, thosegranulatable carrier materials are preferred that are desirable in adetergent composition, e.g. penta sodium or penta potassiumtripolyphosphate.

Coating Layer The coating layer consists of a nonionic surface-activeagent that is liquid or semi-paste-like at room temperature. Highermelting liquefiable nonionic surfaceactive agents may also be used.Examples of suitable nonionic surface-active agents are alkyl phenolswith eight to 18 carbon atoms in the alkyl chain, and condensed with 8to 15 moles of ethylene oxide, such as nonylphenol condensed with 10moles of ethylene oxide, C -C monohydric aliphatic alcohols condensedwith 8 to 25 moles of ethylene oxide, such as tallow fatty alcoholcondensed with 25 moles of ethylene oxide, isotridccyl alcohol condensedwith l 1 moles of ethylene oxide secondary C,,C,,, alcohols condensedwith 9 moles of ethylene oxide, fatty acid monoand dialkylol amides with10 to carbon atoms in the fatty acid residue, and ethoxylatedderivatives thereof. Other suitable nonionics can be found in Schick,MJ. Nonionic Surfactants 1967, which is hereby incorporated by way ofReference.

Acidic Substance The acidic substances that are used in the presentinvention should have an acid pH value, preferably between 4 and 6, in al%-aqueous solution. Any suitable organic and/or inorganic acidsubstance may be used, provided it does not afi'ect the enzymenegatively. suitable examples are acid salts, such as sodium orpotassium acid pyrophosphate, alkali metal acid orthophosphate,inorganic acids such as phosphoric acid, and organic acids like citricacid and the sodium salt thereof, adipic acid and the like.

Particularly preferred are acidic substances which are soluble ordispersible in the nonionic surface-active agent, such as citric acid.

Proteolytic enzymes The proteolytic enzymes which can be used in thepresent invention may be of animal and vegetable origin or may beobtained from micro organisms, including bacteria and fungi. Examples ofsuch proteolytic enzymes are pepsin, trypsin, papain, aspergilluspeptidase. The preferred proteolytic enzymes are those produced by microorganisms, such as the proteases produced by Bacillus subtilis. Thecommercial proteolytic enzymes are normally in the form of a fine powdercontaining the enzymes and an inert carrier material, such as sodium orcalcium sulphate or clay. The preferred proteolytic enzymes are of thesubtilisine type, commercially available under the trade names Alcalaseand Maxatase. Alcalase is a serine protease, produced by Novo lndustrieA/S Copenhagen, by submerged fermentation of a special strain ofBacillus subtilis. Maxatase is also a protease, produced from Bacillussubri'lis, manufactured by the Royal Dutch Fermentation Industries atDelft, Holland.

The granular proteolytic enzyme composition of the present invention canbe prepared in various ways. It is preferred to incorporate the acidicsubstance in the nonionic surface-active agent first, admixing thiscoating material with the granular carrier material and subsequentlyaffixing the proteolytic enzyme powders thereon.

The granular proteolytic enzyme compositions are usually further coatedwith a suitable coating material. Suitable coating materials are those,which are also suitable as coating agents for the core of the granularproteolytic enzyme compositions as described above, but otherfilm-forming agents such as polyvinylalcohol, polyvinylpyrrolidone,shellac, fatty acids, esters, waxes, etc. can be used.

The outer coating layer thus formed may also comprise the acidicsubstance, and it constitutes a preferred embodiment of the presentinvention when the inner and outer layers contain the acidic substance.The layer that contains the acidic substance forms, as it were, anacidic barrier against the harmful influences of e.g. particularingredients of the detergent composition as well as a barrier tomoisture present therein.

The amount of acidic substance required in the present invention isdependent upon the activity of the proteolytic enzymes as well as uponthe amount of proteolytic enzyme present. In general, the granularproteolytic enzyme composition should contain an amount of acidicsubstance such that the weight ratio between the proteolytic enzyme,calculated to a standard activity of 1.5 Anson unit/g, and the acidicsubstance is from 10:1 to 1:10. Preferably the weight ratio is 2:1 to1:2. The ratio between the nonionic surfaceactive agent and acidicsubstance is from 10:1 to 1:1. The acidic substance is from 0.5 to 10percent, preferably from 2 to 8 percent by weight of the granule. Theganular proteolytic enzyme composition is adapted to be particularlyformulated with a detergent composition. Such a detergent compositionmay comprise one or more detergent surfactants, such as anionic andnonionic detergent surfactants, soap and mixtures thereof.

In general, the detergent composition may contain from 2 to 20 percentby weight of an anionid detergent surfactant. Examples thereof arealkylbenzenesulphonates with 12 to 18 carbon atoms in the alkyl group,alkylsulphates with 10 to 24 carbon atoms in the alkyl group,olefinsulphonates prepared by sulphonating straight-chain a-olefms with10 to 20 carbon atoms and subsequently neutralizing and hydrolyzing thesulphonation reaction product, acylisethionates with 12 to 18 carbonatoms in the acyl-group and acyltaurates with 12 to 18 carbon atoms inthe acyl group. The composition may furthermore contain 1 to 10 percentby weight of a nonionic detergent surfactant. Examples thereof are thecondensation products of alkylene oxide, such as ethylene oxide andpropylene oxide with alcohols having from 12 to 24 carbon atoms in thealkyl group, with alkylphenols having from eight to 18 carbon atoms inthe alkyl group, with fatty acid amides with a C -C fatty acid residue,with polyalkyleneglycols and mixed alkylene oxide condensation products.

The compositions may also contain as alkali metal soap in an amount of lto 10 percent by weight. Examples thereof are the alkali metal soaps ofC -C fatty acids, such as palm oil-, hardened fish oil, coconut oil, andtallow fatty acids.

For medium sudsing compositions the amount of the different detergentsurfactants are 8 to 15 percent by weight of the anionic detergentsurfactant 1 to 6 percent by weight of the nonionic detergent surfactant1 to 5 percent by weight of the alkali metal soap whereas for lowsudsing compositions the amounts are: 2 to 9 percent by weight of theanionic detergent surfactant 2 to 10 percent by weight of the nonionicdetergent surfactant 5 to 10 percent by weight of the alkali metal soap.The remaining part of the composition may consist of the normalconstituents of a detergent composition. They may contain from 20 to 50percent of a condensed phosphate, such as pentasodium triphosphate. 1fdesirable, part of the condensed phosphate may be replaced by an organicbuilder, such as trisodium nitrilotriacetate.

Furthermore, from 2 to 10 percent of sodium silicate TABLE ll may bepresent, 0.5 to 3 percent of sodium carbox- 1 ll 1 ther suitablesoil-sus endin Penmdmm y y Ce u 056 P 8 triphosphate s 66 70 66 70 74agent may be present. if des1red, up to 45 percent by Nonyl phenolweight of a bleaching agent, such as sodium perborate 5 moles ofethylene may be added for heavy-duty purposes. made 0 10 10 to 10 Thecompositions may furthermore contain alkali g y gqg 8 4 8 4 metal salts,such as sodium sulphate, sodium carbonate, gg i f 16 sodium borates, andfurthermore other adjuvants, such Alcalase l6 l6 l6 16 1e 16 as tarnishinhibitors, perfumes, germicides, coloring Numb" l 2 3 4 5 Mann agents,lather modifiers, fluorescers, solvents, bleach precursom The granuleswere prepared from granular an- The granular proteolytic enzymecompositions of the y pentasodwm mphosphate havmg a invention may bepresent in an amount of 0.5- per- (50450 cent, preferably 5-10 percent,by weight of the deter- 15 T Rowdfled Pfoteolyuc enzyme Alcalase was gemcomposition. m1xed wlth the ac1d1c substance and subsequently at-Examples of detergent compositions according to the f l to Y F materialby means of "iropwlsc invention will now be given by way of illustrationonly dmon of hqud fmnylphenol condensed 10 moles dm Ji it fi manner. ofethylene mode. The granules thus formed were coated by means of a secondlayer of the nonionic. EXAMPLE I These granules were sieved with a sievewith apertures Granules of the composition as given in Table I were ofmm and add! m an amount of 5 percent to prepared by dry mixing thegranular anhydrous carrier the detergent compos1t1on of Example[.gStorage tests materials having a particle size of 50-250 y. with acomwere "3 out f Several weeks f C 80 mercially available powderedproteolytic enzyme, m lanlmated and l f carton manufactured by submergedfermentation with a strain talnem The residual e zym ic activity wasdeterof Bacillus subtilis known under the trade name Almmedthe resultsofwhlch are Shownm Tablem calase (w1th an act1v1ty of 1.5 Anson umtlg),1n a mlx- TABLE m mg apparatus. Subsequently th1s dry m1xture was 30granulated by quickly dropwise adding liquid nol r d a a i ity (in granue nylphenol condensed with 10 moles of ethylene oxide, l week 3 weeks 4weeks 6 weeks 8 weeks to whlch c1tr1c ac1d had been added first. Thegranules not not not not not obtained were then sieved with a sievehaving apertures l m m l l of 0.5-1 mm andadded in an amount of5 percentto 1 88 59 "1; 47 15 detergent compositlon of the following formula: 257 109 12 74 o 19 0 as 0 47 3 5O 96 i0 77 5 72 0 36 0 5O 4 37 i0 54 5 440 25 0 l4 sodium salt of straight ehaln 5 35 97 i2 72 4 5i 4 40 0 22dodecylbenzenesulphonate 5.5 6 26 78 9 56 l 44 0 24 0 9 sodium soap ofcommercial stearic acid 8.0 40 nonylphenol condensed with l4 moles ofethylene oxide 3.0 EXAMPLE "I 3:2 Several enzyme-containing granuleswere prepared sodium carboxymethylcellulose 1.0 from granularpentasodium triphosphate which had a gggfi figg gf 33g particle size of50-250 1; and a powdered proteolytic wamPeHumeem my 45 enzyme fromBacillus subtilis, sold under the trade name Maxatase. The compositionof the granules is The residual activity of the proteolytic enzyme wasgiven in Table IV. determined after 7 days storage of the detergent com-Granules nos. 1 and 4 were prepared in the following position with theenzyme granules at 30C and 80 perway. Citric acid was dispersed intallow fatty alcohol cent R.H.The results are given in Table l.condensed with 25 moles of ethylene oxide, under TABLE 1 GluingGrenulatable carrier agent,

material nonylphenol Anhydrous Anhydrous condensed Percent pentasodiumdlsodium Enzyme, with 10 residual triphosacid pyroalcalase Acidic molesof activity Number phate phosphate (proteolytic substance ethylene alterof granule (powder) (powder) enzyme) citric acid oxide 7 days EXAMPLE ll5 heating to C in a homogenisator for half an hour. The dispersion was aclear liquid, which became Granules were prepared of the composition asgiven viscous at lower temperatures. This dispersion was in Table ll.heated up and sprayed on the granular pentasodium triphosphate by meansof a two-fluid nozzle. Subsequently the powdered enzymes were added, andon the so-obtained granules again the dispersion of citric acid in thenonionic was sprayed.

Granules nos. 2 and 6 were prepared in an identical way, with theexception that first solely the tallow fatty alcohol condensed with 25moles of ethylene oxide was sprayed onto the granular pentasodiumtriphosphate, and after addition of the proteolytic enzyme powders thecitric acid nonionic dispersion was sprayed on the granules so obtained.

Granules nos. 3 and 5 were prepared as follows. On

the granular pentasodium triphosphate first the tallow fatty alcoholcondensed with 25 moles of ethylene oxide was sprayed, followed by theaddition of the dry mixture of the proteolytic enzyme powder and citricacid, and subsequently again the nonionic was sprayed upon the granules.

Granule no. 7 was prepared by spraying the nonionic on the granularpentasodium triphosphate, adding the enzyme powder and again sprayingthe nonionic thereupon. Granule no. 7 was made for comparison purposes.All the granules contained 5 percent nonionic in the inner and 5 percentnonionic in the outer layer. From each of these granules, 7.5 percent byweight was added to the detergent composition as given in Example I, andthe residual proteolytic activity was determined after 7 days' storageof the composition at 30C and 80 percent relative humidity. The resultsare also given in Table IV.

TAB LE IV Granular carrier Percent material, citric Percent Parcmttpercent acid in citric citric pentainner acid dry acid in lcrcent sodiumlayer mixed outer residual Granule. trlphos- (5% with 16% layerproteolytic number phate nonionic) enzyme (5%) activity What is claimedis:

l. A granular proteolytic enzyme composition, adapted to be formulatedwith a detergent composition, the proteolytic enzyme compositionconsisting essentially of t i. a core of a non-acidic, non-hygroscopic,nonfriable carrier material selected from the group consisting ofalkalimetaltripolyphosphates, -pyrophosphates, -orthophosphates,alkalimetalsulphates, -borates, silicates, -carbonates, gelatinizedstarch and starch derivatives,

. a coating layer enrobing said core, consisting of a nonionic detergentsurfactant selected from the group of alkyl phenols with eight to 18carbon atoms in the alkyl chain, and condensed with 8 to 15 moles ofethylene oxide, C C monohydric aliphatic alcohols condensed with 6 to 25moles of ethylene oxide, secondary C alcohols condensed with 9 moles ofethylene oxide, fatty acid mono and dialkyiol amides with 10 to carbonatoms in the fatty acid residue, and ethoxylated derivatives thereof,

iii. an acidic substance, dissolved or dispersed in said coating layer,said acidic substance having a pH of 4 to 6 in a Flu-aqueous solution,selected from the group consisting of citric acid, and adipic acid, saidacidic substance being present in an amount of 0.5 to 10 percent byweight of the granule, the weight ratio between the nonionic detergentsurfactant coating layer and the acidic substance being from 10:1 to1:1,

iiii. proteolytic enzymes, attached to the coating layer of the core, insuch an amount that the weight ratio between the proteolytic activity,calculated to a standard activity of 1.5 Anson unit/g, and the acidicsubstance is from 10:1 to 1:10.

2. A composition according to claim 1, in which the granular proteolyticenzyme composition comprises furthermore an outer coating layer of thenonionic detergent surfactant, in which the acidic substance has beendispersed or dissolved.

3. A composition according to claim 1, in which the acidic substance iscitric acid.

4. A composition according to claim 1, in which the amount of the acidicsubstance is from 2 to 8 percent by weight of the granule.

5. A detergent composition consisting essentially of a. from 2 to 20percent by weight of an anionic detergent surfactant selected from thegroup consisting of alkylbenzenesulphonates with 12 to 18 carbon atomsin the alkyl group, alkylsulphonates with 10 to 24 carbon atoms in thealkyl group, olefinesulphonates with 10 to 20 carbon atoms,acylisethionates with 12 to 18 carbon atoms in the acyl group andacyltaurates with 12 to 18 carbon atoms in the acyl group.

. from 1 to 10 percent by weight of a nonionic detergent surfactantselected from the group consisting of the condensation products ofethylene oxide or propylene oxide with alcohols having from 12 to 24carbon atoms in the alkyl group, with alkylphenols having from eight to18 carbon atoms in the alkyl group, with fatty acid amides with a C -Cfatty acid residue, with polyalkyleneglycols and with mixed alkyleneoxide condensation products,

. from 1 to 10 percent by weight of an alkalimetal soap of C,,-C fattyacids,

. from 20 to 50 percent by weight ofa water-soluble alkalimetal buildersalt,

. from 0 to 45 percent by weight of a bleaching agent,

f. from 0.5 to 15 percent by weight of a granular proteolytic enzymecomposition consisting essentially of i. a core of a non-acidic,non-hygroscopic, non-friable carrier material selected from the groupconsisting of a1kalimetaltripolyphosphates, pyrophosphates,-orthophosphates, alkalimetalsulphates, -borates, -si1icates,-carbonates, gelatinized starch and starch derivatives,

ii. a coating layer enrobing said core, consisting of a nonionicdetergent surfactant selected from the group of alkyl phenols with eightto 18 carbon atoms in the alkyl chain, and condensed with 8 to 15 molesof ethylene oxide, C,C, monohydric aliphatic alcohols condensed with 6to 25 moles of ethylene oxide, secondary C -C alcohols condensed with 9moles of ethylene oxide, fatty acid monoand dialkylol amides in thefatty acid residue, and ethoxylated derivatives thereof,

iii. an acidic substance, dissolved or dispersed in the granule, theweight ratio between the nonionic detergent surfactant coating layer andthe acidic substance being from 10:1 to 1:1.

iiii. proteolytic enzymes, attached to the coating layer of the core, insuch an amount that the weight ratio between the proteolytic activity,calculated to a standard activity of 1.5 Anson unit/g, and the acidicsubstance is from 10:1 to 1:10.

2. A composition according to claim 1, in which the granular proteolyticenzyme composition comprises furthermore an outer coating layer of thenonionic detergent surfactant, in which the acidic substance has beendispersed or dissolved.
 3. A composition according to claim 1, in whichthe acidic substance is citric acid.
 4. A composition according to claim1, in which the amount of the acidic substance is from 2 to 8 percent byweight of the granule.
 5. A detergent composition consisting essentiallyof a. from 2 to 20 percent by weight of an anionic detergent surfactantselected from the group consisting of alkylbenzenesulphonates with 12 to18 carbon atoms in the alkyl group, alkylsulphonates with 10 to 24carbon atoms in the alkyl group, olefinesulphonates with 10 to 20 carbonatoms, acylisethionates with 12 to 18 carbon atoms in the acyl group andacyltaurates with 12 to 18 carbon atoms in the acyl group. b. from 1 to10 percent by weight of a nonionic detergent surfactant selected fromthe group consisting of the condensation products of ethylene oxide orpropylene oxide with alcohols having from 12 to 24 carbon atoms in thealkyl group, with alkylphenols having from eight to 18 carbon atoms inthe alkyl group, with fatty acid amides with a C10-C24 fatty acidresidue, with polyalkyleneglycols and with mixed alkylene oxidecondensation products, c. from 1 to 10 percent by weight of analkalimetal soap of C12-C22 fatty acids, d. from 20 to 50 percent byweight of a water-soluble alkalimetal builder salt, e. from 0 to 45percent by weight of a bleaching agent, f. from 0.5 to 15 percent byweight of a granular proteolytic enzyme composition consistingessentially of i. a core of a non-acidic, non-hygroscopic, non-friablecarrier material selected from the group consisting ofalkalimetaltripolyphosphates, -pyrophosphates, -orthophosphates,alkalimetalsulphates, -borates, -silicates, -carbonates, gelatinizedstarch and starch derivatives, ii. a coating layer enrobing said core,consisting of a nonionic detergent surfactant selected from the group ofalkyl phenols with eight to 18 carbon atoms in the alkyl chain, andcondensed with 8 to 15 moles of ethylene oxide, C8-C20 monohydricaliphatic alcohols condensed with 6 to 25 moles of ethylene oxide,secondary C11-C15 alcohols condensed with 9 moles of ethylene oxide,fatty acid mono- and dialkylol amides in the fatty acid residue, andethoxylated derivatives thereof, iii. an acidic substance, dissolved ordispersed in said coating layer, said acidic substance having a pH of 4to 6 in a 1%-aqueous solution, selected from the group consisting ofcitric acid and adipic acid, said acidic substance being present in anamount of 0.5 to 10 percent by weight of the granule, the weight ratiobetween the nonionic detergent surfactant coating layer and the acidicsubstance being from 10:1 to 1:1. iiii. proteolytic enzymes, attached tothe coating layer of the core, in such an amount that the weight ratiobetween the proteolytic activity, calculated to a standard activity of1.5 Anson unit/g, and the acidic substance is from 10:1 to 1:10.